The findings, published Wednesday by Health Affairs, are considered the authoritative breakdown of American health care spending and are prepared each year by the Centers for Medicare and Medicaid Services.

The overall rate of increase in health care spending experienced a slight slowdown over the previous year, driven in part by the expected moderation in growth after the expansion of insurance coverage through the Affordable Care Act. There was also a sharp decrease in the growth of prescription drug expenditures, as hepatitis C treatment costs have declined and fewer patients are receiving them.

But even as spending growth slowed, health expenditures swallowed a greater part of the economy, with health expenditures making up 17.9 percent share of gross domestic product in 2016.

The slowdown in spending growth — a 4.3 percent increase in 2016, following a 5.8 percent growth the previous year — stemmed from changes in a broad array of health care sectors.

That ranged from slower growth in Medicaid spending after the surge in enrollment caused by the Affordable Care Act expansion, to a marked slowdown in prescription drug spending growth that had been pushed higher by the approval of a new, expensive treatment for hepatitis C in 2013.

A shift toward insurance plans that transfer more of the burden of health care costs onto patients helped fuel the rise in out-of-pocket costs. In 2016, 29 percent of people who receive insurance through employers were enrolled in high-deductible plans, up from 20 percent in 2014. The size of the deductibles also increased over this time period, a 12 percent increase in 2016 for individual plans, compared with a 7 percent increase in 2014.

Out-of-pocket spending grew the most on medical equipment and supplies and decreased slightly for prescription drugs, according to the analysis.

The most noticeable change was a big slowdown in prescription drug spending growth, which made up 10 percent of the total spending, or $328.6 billion. (That spending number does not include drugs administered by physicians or hospitals.)

That decrease highlights the effect that expensive new treatments used by large numbers of people can have on national spending. A new generation of expensive hepatitis C drugs drove national drug spending 12.4 percent higher in 2014 and 8.9 percent higher in 2015. In 2016, the prescription drug spending increased by 1.3 percent, closer to the rates in the years before the new drugs were approved.

The authors of the report attributed that trend not just to hepatitis C drugs. There were also fewer new, brand name drugs approved in 2016 — 22 new drugs, compared with 45 the previous year. Another factor was a slowdown in the growth of spending on insulin, a lifesaving drug for people with diabetes, in Medicare.

Insulin prices have been under intense scrutiny as drugmakers have increased the list prices of insulin while claiming the true cost to patients has remained flat due to discounts and rebates

Health care spending has been buffeted by unusual changes during the past decade. There was a historic slowdown in growth due to the Great Recession, and then the Affordable Care Act's expansion of health insurance coverage fueled spending.

The authors said this year's trend of slower growth could be a sign that things were returning to normal.

“Future health expenditure trends are expected to be mostly influenced by changes in economic conditions and demographics, as has historically been the case,” the authors wrote.